An electrophotographic apparatus includes several systems, including a latent image-forming system, which applies a uniform potential to a photoreceptive material. The latent image-forming system then applies light to the photoreceptive material in an image-wise pattern to create a latent image corresponding to an image held within the electrophotographic apparatus or some other image source. The image held by the electrophotographic apparatus can be acquired, for example, from an original document or copy sheet, or from desktop publishing computer software.
A toner deposition system within the electrophotographic apparatus applies a conductive, solid or liquid toner to the photoreceptive material which collects on photoreceptive material in a pattern similar to image-wise pattern. A transfer system transfers the inked image from the photoreceptive material either directly onto a final substrate, such as a sheet of paper, or onto an intermediate substrate before being subsequently transferred to the final substrate.
A first transport mechanism transports the photoreceptive material within the electrophotographic apparatus and through the previously mentioned systems. In addition, a second transport mechanism transports the input sheet to and from the toner transfer mechanism.
Commonly, the photoreceptive material is a material which is coated onto a drum or belt, depending on the type of electrophotographic apparatus. After numerous passes within the electrophotographic apparatus, the photoreceptive material can require replacement. When the photoreceptive material is coated onto the drum, replacing the photoreceptive material requires replacing the entire drum, which can be costly and difficult to accomplish.
When the photoreceptive material is coated onto a belt, replacement cost is reduced in comparison. However, removing the spent belt and replacing it with a new belt requires disassembly of the belt transport mechanism, which is difficult and time-consuming. If, however, the belt transport mechanism is made using cantilevered rollers, disassembly is simplified. But, a cantilevered belt transport mechanism is more complex and requires significant structural support within the electrophotographic apparatus to provide a sufficiently stable transport path for the belt. Such support adds cost, size, and weight to the electrophotographic apparatus.
In addition, a belt inherently includes a seam. Seams are often made by thermally fusing the two ends of a web together. This, of course, limits the type of material of which the belt may be constructed, namely, thermally fusible material. Plus, because seaming creates irregularities in the photoreceptive material along the seam, the quality of the image can be adversely affected when the image is imposed across the seam.
U.S. Pat. No. 4,088,403 (inventor: Kingsley) discloses coating the photoreceptive material onto a length of carrier material to create a photoconductive belt. The belt must be stretched around a sub-belt so that the photoconductive belt is under tension and so that the ends of the belt are brought together or overlap each other to form a joined belt. The leading and trailing edges are either adhered to the sub-belt or are attached to each other with means such as adhesive or a hook-and-loop fastener. With this construction, the photoconductive belt can be wrinkled or excessively stretched as it is transported with the sub-belt. In addition, this photoconductive belt is not easily removed and replaced with a new belt within the apparatus in which it functions, such as an electrophotographic apparatus.